Automotive vehicles equipped with shoulder belt retractors, particularly in the United States, include "comfort feature" means for relieving uncomfortable retraction belt tension on the occupant. Typically, a shoulder belt retractor includes a coiled spring actuated wind-up reel for the belt webbing which passes through a static loop mounted on the vehicle door pillar above occupant's shoulder from which the belt extends across the chest of the occupant to a buckle latch at an inside anchor point. Upon reaching a sitting position with engagement of the shoulder belt retacted under wind-up belt tension, the comfort feature enables the occupant to manually extract the belt to a loosened condition upon which a latch in the retractor mechanism locks the belt against retraction. Such comfort feature is desirable to relieve the occupant from uncomfortable shoulder belt retraction force which often deters an occupant from using the shoulder belt with its safety advantages.
Extraction of the shoulder belt against the retractor spool wind-up spring is normally permitted in an emergency locking retractor having an inertia responsive locking system against extraction. Accordingly, extraction can be accommodated not only to initially secure the belt buckle, as in a nonpassive manual system, but also permits the occupant to move away from the seat back, as when the driver reaches into the glove compartment or otherwise. This has necessitated a sophisticated comfort feature locking mechanism which will cause release of the comfort feature locking mechanism from an overextended extraction subject to manual resetting upon return to normal sitting position.
Typical functional requirements established by a United States Automotive Vehicle manufacturer are as follows: